You would know if its not enough. Just follow your instincts and babies cues. My lo will sometimes go a whole day without any type of solids and other days he goes through lots. He'll let you know. By the way, if you're feeding him cereal, you might want to do some research on the ingredients. Cereal for babies has lots of very yucky ingredients that you probably wouldn't want to give your baby if you knew they were in there. (including traces of arsnic!) Also it has almost know nutritional value despite what the box says and is a waste of calories. You may not agree with me and that is totally cool, but a little research can never hurt when it comes to the wellbeing of our little ones right?